Circuit breakers are typically situated in electrical enclosures, or panels, and are used to control the availability of current for connected electrical circuits. A panel typically includes a plurality of circuit breakers and may include a plurality of rows of circuit breakers. Typically, a panel is connected to a physical structure such as a wall or building side and the power to the panel is sourced from an electric power grid through a rated meter. In operation, a circuit breaker is activated to disrupt power to a circuit upon the occurrence of an event such as an overload, over-demand, short-circuit, etc., and are used for most every power source access point to a residence, an industrial facility, etc.
A circuit breaker safety switch (CBSS) is a device which also includes circuit breakers. A CBSS is typically designed for large photovoltaic (PV) solar systems and is intended for installation next to an inverter, for instance. A CBSS provides multiple UL 1000V load-break circuit breakers combined into one easy-to-install, safe compact enclosure. A CBSS, similar to a panel, provides circuit protection and individual disconnects but also eliminates fuses, provides for compliance with varied disconnect and core requirements and also provides for complete isolation of inverter fuses.
Load-break switches are another type of safety switch which may also be used to isolate a PV system (typically on the DC-current side), although a load-break switch is typically larger than the traditional-style and may therefore present more of a challenge to fit more of them into a panel, for instance.
Users, operators and others who have access to the source of power (power system) entering a particular location, may have a need to disconnect one or more of the power inputs to the power system from a power feed source. For example, if one of the power sources fails, or a connection in the system fails, then the power inputs need to be disconnected from the load so that the faulty components can be repaired or replaced without exposing one who is to access the panel to high voltage or current. In typical power systems, a safety switch can be connected between a power source and other component using the power. For example, a safety switch can be connected between a combiner and an inverter in a solar power system, or between a combiner and a recombiner.
However, traditional safety switches are often expensive and may be labor-intensive to install and maintain. Typically, a safety switch is provided in each enclosure, such as a metal cabinet, and several enclosures must be provided to allow for safety disconnects for several power lines. A conduit with heavy protective cladding must also be routed from a power connection to each safety switch enclosure. If multiple power lines are used, such as in solar power systems, a safety enclosure on each power line becomes burdensome and adds further expense in an installation. Further, as an enclosure becomes more crowded due to the presence of switches and other components, its operation and access also becomes more difficult.
Therefore, it is advantageous to be able to access such switches in an inactive state, where the person accessing the switch can ensure that the power to the switch is disconnected, in part to avoid additional delays and costs. However, given the complexity of traditional safety switches, determining the condition of the state for such is difficult. Similarly, having only a window or similar cut-out access to “see inside” the enclosure would be ineffective, particularly in cases where a load-break switch is used where its arcing would soon render the window clouded or opaque. Therefore, what is desired is a safety switch which provides a user the ability to visibly determine the state or status of the connection of the device to a power source, where separation of contacts may be determined, for instance.
As used herein, the terms CBSS, load-break switches, non-load-break switches, circuit breakers and the like, are intended to be used interchangeably, and may comprise a portion or totality of a switch or safety switch.